Buggy code:
public class Trainer { private static final Logger log = Logger . getLogger ( Trainer . class ) ; public static final int DEFAULT_CAPACITY = 16 ; public static final float DEFAULT_LOAD = ( ( float ) ( 0.75 ) ) ; protected int nthreads = 1 ; protected int throttle ; protected SRW learner ; protected int epoch ; LossData lossLastEpoch ; public Trainer ( SRW learner , int nthreads , int throttle ) { } public Trainer ( SRW srw ) { } private ParamVector createParamVector ( ) { } public void doExample ( PosNegRWExample x , ParamVector < String , ? > paramVec , boolean traceLosses ) { } public ParamVector train ( Iterable < PosNegRWExample > examples , int numEpochs , boolean traceLosses ) { } public ParamVector train ( Iterable < PosNegRWExample > examples , ParamVector initialParamVec , int numEpochs , boolean traceLosses ) { ParamVector paramVec = this . learner . setupParams ( initialParamVec ) ; if ( ( paramVec . size ( ) ) == 0 ) for ( String f : this . learner . untrainedFeatures ( ) ) paramVec . put ( f , this . learner . getWeightingScheme ( ) . defaultWeight ( ) ) ; Multithreading < Trainer . FQTrainingExample , Integer > m = new Multithreading < Trainer . FQTrainingExample , Integer > ( Trainer . log ) ; for ( int i = 0 ; i < numEpochs ; i ++ ) { ( this . epoch ) ++ ; this . learner . setEpoch ( epoch ) ; Trainer . log . info ( ( ( "epoch<seq2seq4repair_space>" + ( epoch ) ) + "<seq2seq4repair_space>..." ) ) ; this . learner . clearLoss ( ) ; numExamplesThisEpoch = 0 ; if ( examples instanceof FileBackedIterable ) ( ( FileBackedIterable ) ( examples ) ) . wrap ( ) ; m . executeJob ( this . nthreads , new Trainer . FQTrainingExampleStreamer ( examples , paramVec ) , new edu . cmu . ml . proppr . util . multithreading . Transformer < Trainer . FQTrainingExample , Integer > ( ) { @ Override public Callable < Integer > transformer ( Trainer . FQTrainingExample in , int id ) { return new Trainer . Train ( in , id ) ; } } , new edu . cmu . ml . proppr . util . multithreading . Cleanup < Integer > ( ) { @ Override public Runnable cleanup ( Future < Integer > in , int id ) { return new Trainer . TraceLosses ( in , id ) ; } } , this . throttle ) ; this . learner . cleanupParams ( paramVec ) ; if ( traceLosses ) { LossData lossThisEpoch = this . learner . cumulativeLoss ( ) ; for ( Map . Entry < LOSS , Double > e : lossThisEpoch . loss . entrySet ( ) ) e . setValue ( ( ( e . getValue ( ) ) // ( numExamplesThisEpoch ) ) ) ; System . out . print ( ( ( ( ( "avg<seq2seq4repair_space>training<seq2seq4repair_space>loss<seq2seq4repair_space>" + ( lossThisEpoch . total ( ) ) ) + "<seq2seq4repair_space>on<seq2seq4repair_space>" ) + ( numExamplesThisEpoch ) ) + "<seq2seq4repair_space>examples" ) ) ; System . out . print ( ( "<seq2seq4repair_space>=log:reg<seq2seq4repair_space>" + ( lossThisEpoch . loss . get ( LOG ) ) ) ) ; System . out . print ( ( "<seq2seq4repair_space>:<seq2seq4repair_space>" + ( lossThisEpoch . loss . get ( REGULARIZATION ) ) ) ) ; if ( ( epoch ) > 1 ) { LossData diff = lossLastEpoch . diff ( lossThisEpoch ) ; System . out . println ( ( ( ( ( ( ( "<seq2seq4repair_space>improved<seq2seq4repair_space>by<seq2seq4repair_space>" + ( diff . total ( ) ) ) + "<seq2seq4repair_space>(log:reg<seq2seq4repair_space>" ) + ( diff . loss . get ( LOG ) ) ) + ":" ) + ( diff . loss . get ( REGULARIZATION ) ) ) + ")" ) ) ; if ( ( diff . total ( ) ) < 0.0 ) { <START_BUG> System . out . println ( ( ( "WARNING:<seq2seq4repair_space>loss<seq2seq4repair_space>INCREASED<seq2seq4repair_space>by<seq2seq4repair_space>" + ( diff . total ( ) ) ) + "<seq2seq4repair_space>-<seq2seq4repair_space>what's<seq2seq4repair_space>THAT<seq2seq4repair_space>about?" ) ) ; <END_BUG> } } else System . out . println ( ) ; lossLastEpoch = lossThisEpoch ; } } return paramVec ; } public TObjectDoubleMap < String > findGradient ( GroundedExampleStreamer examples , ParamVector paramVec ) { } private class FQTrainingExample { PosNegRWExample x ; ParamVector paramVec ; SRW learner ; public FQTrainingExample ( PosNegRWExample x , ParamVector paramVec , SRW learner ) { } } private class Train implements Callable < Integer > { Trainer . FQTrainingExample in ; int id ; public Train ( Trainer . FQTrainingExample in , int id ) { } @ Override public Integer call ( ) throws Exception { } } protected int numExamplesThisEpoch ; private class TraceLosses implements Runnable { Future < Integer > in ; int id ; public TraceLosses ( Future < Integer > in , int id ) { } @ Override public void run ( ) { } } private class FQTrainingExampleStreamer implements Iterable < Trainer . FQTrainingExample > , Iterator < Trainer . FQTrainingExample > { Iterator < PosNegRWExample > examples ; ParamVector paramVec ; public FQTrainingExampleStreamer ( Iterable < PosNegRWExample > examples , ParamVector paramVec ) { } @ Override public Iterator < Trainer . FQTrainingExample > iterator ( ) { } @ Override public boolean hasNext ( ) { } @ Override public Trainer . FQTrainingExample next ( ) { } @ Override public void remove ( ) { } } public static void main ( String [ ] args ) { } }

Fix:
System . out . println ( ( ( "WARNING:<seq2seq4repair_space>loss<seq2seq4repair_space>INCREASED<seq2seq4repair_space>by<seq2seq4repair_space>" + ( - ( diff . total ( ) ) ) ) + "<seq2seq4repair_space>-<seq2seq4repair_space>what's<seq2seq4repair_space>THAT<seq2seq4repair_space>about?" ) ) ;